‘This is a wonderful book that should be on the desk of every architect and planner. It shows how

Can we also create ‘extra’ financial incentives to promote ecological space? 
Yes. Incentives like exemptions to planning provisions for sunspaces would increase ecological and 
environmental values without added resource-intensive infrastructure – and with very little increase 
in land coverage or public infrastructure. There is a constant turnover of properties and, just as many 
people renovate homes for resale, businesses could develop a specialization in eco-retrofitting homes 
for resale. We could create additional incentives by enabling ‘non-owners’ to develop ecological 
space in cities, suburbs and buildings. This would be achieved by de-coupling space from land area 
and buildings (similar to mining rights, TDRs and carbon trading systems). Thus, for example, 
homeowners could sell the right to develop part of their property (eg yard or roof) for urban food 
or solar electricity production purposes. This could be seen as a ‘reverse TDR’, as people would 
acquire the right to use another’s building, property or infrastructure, either through purchase or a 
percentage of profits. Added income to homeowners from the use of their property for eco-productive 
activity by others could enable elderly residents to stay in their homes longer – as more and more are 
choosing to do. Grants or trading systems that reward eco-retrofitting for ecological space could be 
implemented by ‘eco-retrofitting banks’ that sell points or credits to developers who need them to 
obtain development approvals. Similarly, as mentioned earlier, mortgage systems can offer incentives 
for eco-retrofitting that increases the ecological base of cities, just as they are now sometimes used 
to reward people for energy-efficient homes.
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How would ecological space be quantified for TDR or trading purposes?
There are various ways of quantifying this. Since ecosystems defy measurement, all we need to do is 
select relevant ‘surrogates’.
Passive
solar heating, cooling and ventilating, for example, are eco-services 
provided by nature (sun, wind, etc). It is easy to measure the financial benefits of eco-services in 
building design. We can, for example: 
•
Read the energy and water meter (instead of predicting performance).
• 
Measure the costs and risks of mechanical air-conditioning equipment that is avoided. A
factor that should be considered is that eco-services need not entail risks. We do not
calculate the risks of explosions of fossil fuel systems (eg gas), and we do not calculate the
risks of ‘brown outs’ of centralized electricity eg coal).
• 
Measure the square metres allocated to things such as vertical landscapes, or the amount of
productive soil that the building infrastructure supports in roofs, decks, ground floor,
balconies, atriums or green walls.
• 
Measure the health of the air, water and soil that comes out of the building or neighbourhood 
relative to their quality before they entered the building or neighbourhood. Community or 
individual biological water-treatment systems already require ongoing testing for public
health reasons. Testing improvement in water, indoor air or soil quality is not onerous
either. Soil samples of the mechanical properties of development sites have long been
required for structural engineering purposes. There are already many kinds of soil testing
services that measure the biological health and carbon content of the soil (although some
argue the science is not settled).
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